- Add RD_TROUBLED state for items that need to start recovery, and rename

- Add RD_TROUBLED state for items that need to start recovery, and rename
  the rd_state values to RD_*, to avoid namespace conflict with the recovd_state
  values.
- Gobs of debugging and NULL-checking in expired_completion_wait, trying to track
  down a can't-happen OOPS that phil is seeing.
- Better error reporting in the case where we can't run the recovery upcall.
- Disable the silly immediate restart of a failed client recovery, because it
  causes a nice tight loop in the case that we can't run the recovery upcall.
- Mild .cvsignore fixes.